Two years' experience of implementing molecular screening of hepatitis B virus, hepatitis C virus and human immunodeficiency virus 1, 2 in Riyadh blood donors.

Molecular screening technologies have improved blood safety by reducing the number of window-period transmissions relative to serological screening. In the two years following the introduction of molecular testing in King Khalid University Hospital, Saudi Arabia, 25,920 donor samples were screened in parallel by both serological and molecular techniques for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV). No HCV or HIV NAT yields were detected. However, molecular screening enabled the interdiction of two confirmed HBV NAT yields. This is only the second report of confirmed HBV NAT yield in the Kingdom of Saudi Arabia, and amongst the few reports in the wider Middle East and North Africa region.

Clinical evaluation of a loop-mediated amplification kit for diagnosis of imported malaria.

BACKGROUND: Diagnosis of malaria relies on parasite detection by microscopy or antigen detection; both fail to detect low-density infections. New tests providing rapid, sensitive diagnosis with minimal need for training would enhance both malaria diagnosis and malaria control activities. We determined the diagnostic accuracy of a new loop-mediated amplification (LAMP) kit in febrile returned travelers. METHODS: The kit was evaluated in sequential blood samples from returned travelers sent for pathogen testing to a specialist parasitology laboratory. Microscopy was performed, and then malaria LAMP was performed using Plasmodium genus and Plasmodium falciparum-specific tests in parallel. Nested polymerase chain reaction (PCR) was performed on all samples as the reference standard. Primary outcome measures for diagnostic accuracy were sensitivity and specificity of LAMP results, compared with those of nested PCR. RESULTS: A total of 705 samples were tested in the primary analysis. Sensitivity and specificity were 98.4% and 98.1%, respectively, for the LAMP P. falciparum primers and 97.0% and 99.2%, respectively, for the Plasmodium genus primers. Post hoc repeat PCR analysis of all 15 tests with discrepant results resolved 4 results in favor of LAMP, suggesting that the primary analysis had underestimated diagnostic accuracy. CONCLUSIONS: Malaria LAMP had a diagnostic accuracy similar to that of nested PCR, with a greatly reduced time to result, and was superior to expert microscopy.

Microbial surveillance of Hajj tents: Bioaerosol sampling coupled with real-time multiplex PCR.

BACKGROUND: Respiratory tract infections are common among pilgrims attending annual Hajj in Mecca, Saudi Arabia. Pilgrims typically spend most of the Hajj period inside ventilated tents, where microorganisms may be transmitted through bioaerosols and droplets. OBJECTIVE: To perform microorganism surveillance inside Hajj tents and assess the similarities between microorganisms isolated from tent bioaerosol samples and nasopharyngeal swabs (NP) of tent occupants. METHODS: Respiratory microorganisms in bioaerosols collected from Hajj tents over a 4-day period were compared with NP of tent occupants using real-time multiplex polymerase chain reaction analysis. RESULTS: A total of 152 samples were collected: 120 tent bioaerosol samples collected on days 9, 10, 11, and 12 of Dhu al-Hijjah, and 32 NP collected on day 12 of Dhu al-Hijjah (corresponding to 23/08/2018). Eighty-three (69.2%) bioaerosol samples tested positive for at least 1 microorganism, with the number of pathogens increasing over the 4 days of sampling. Twenty-seven (84.38%) NP swabs from tent occupants also tested positive. Microorganisms identified in pilgrim nasal carriage and tent bioaerosol samples were similar, and included K. pneumonia, S. aureus, S. pneumonia, human adenovirus, Moraxella, influenza A, and H. influenza. CONCLUSIONS: The data suggest that the Hajj tent environment may contribute to the spread of airborne infections during Hajj. This can have important ramifications for novel pathogens with pandemic potential.

Clinical validation of 3 commercial real-time reverse transcriptase polymerase chain reaction assays for the detection of Middle East respiratory syndrome coronavirus from upper respiratory tract specimens.

Since discovery of Middle East respiratory syndrome coronavirus (MERS-CoV), a novel betacoronavirus first isolated and characterized in 2012, MERS-CoV real-time reverse transcriptase polymerase chain reaction (rRT-PCR) assays represent one of the most rapidly expanding commercial tests. However, in the absence of extensive evaluations of these assays on positive clinical material of different sources, evaluating their diagnostic effectiveness remains challenging. We describe the diagnostic performance evaluation of 3 common commercial MERS-CoV rRT-PCR assays on a large panel (n = 234) of upper respiratory tract specimens collected during an outbreak episode in Saudi Arabia. Assays were compared to the RealStar® MERS-CoV RT-PCR (Alton Diagnostics, Hamburg, Germany) assay as the gold standard. Results showed i) the TIB MolBiol® LightMix UpE and Orf1a assays (TIB MolBiol, Berlin, Germany) to be the most sensitive, followed by ii) the Anyplex™ Seegene MERS-CoV assay (Seegene, Seoul, Korea), and finally iii) the PrimerDesign™ Genesig® HCoV_2012 assay (PrimerDesign, England, United Kingdom). We also evaluate a modified protocol for the PrimerDesign™ Genesig® HCoV_2012 assay.

Assessing the Detection of Middle East Respiratory Syndrome Coronavirus IgG in Suspected and Proven Cases of Middle East Respiratory Syndrome Coronavirus Infection.

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory disease with significant mortality. Two testing methods are currently used for MERS-CoV diagnostics: nucleic acid detection (the gold standard) and serological analysis. In this study, we evaluated the detection of MERS-CoV-IgG in suspected and proven cases of MERS-CoV infection. We enrolled 174 patients: 113 had respiratory symptoms/suspected MERS-CoV infection, 31 had confirmed influenza A or B infection, 23 had a recent confirmed MERS-CoV infection, and 7 had confirmed MERS-CoV infection 1 year before. All underwent MERS-CoV RNA and MERS-CoV-IgG testing. Thirty patients were found to be MERS-CoV RNA positive; however, during serological analysis, only 6 (3.4%) patients were positive for MERS-CoV-IgG, 1 (0.6%) patient was equivocal, and 167 (96%) patients were negative. Among the serological positives, four were recently MERS-CoV RNA positive and two were MERS-CoV RNA negative. No cross-reactivity to influenza A or B was detected. Based on the lack of correlation between nucleic acid and serological analysis, we conclude that MERS-CoV-IgG testing may not be suitable for diagnosing acute infection or estimating its prevalence during an outbreak. In addition, our findings show that MERS-CoV-IgG may not have significant value in determining disease severity or prognosis.